US 2821814 A
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Description (OCR text may contain errors)
Feb. 4, A1958 M. E. FRlTzE SANDBLAST'I'NG TOOL 'Original Filed Jan. 5, 1953 ANN.
INVENTOR. MARVIN E. FRITZE ATTORNEYS Unite States Patent O SANDBLASTING TOOL Marvin E. Fritze, Enumclaw, Wash., assignor of one-half to El. C. Fennelly Company, San Francisco, Calif., and nner-half to Donald E. Hilliard, Seattle, Wash.
@riginal application January 5, 1953, Serial No. 329,516, now Patent No. 2,739,424, dated March 27, 1956. Divided and this application March 22, 1956, Serial No. 573,159
Claims. (Cl. 51-11) This application is a division of application, Serial No. 329,516, filed January 5, 1953, and issuing to United States Patent No. 2,739,424, March 27, 1956.
Pipe is often rusted, corroded, or coated interiorly, and it is a tedious and expensive job to remove the scale, rust and other foreign material which collects upon it, and to recondition the pipe for use. There are Sandblasting tools provided for the purpose, but owing to the highly abrasive nature of the sand or like particulate material used in the Sandblasting operation, such tools in the forms heretofore devised have quickly worn away. Moreover, being of the general nature of nozzles that, of apparent necessity, have been directed angularly with respect to the axis along which the sandblast material is delivered (which must `coincide roughly with the pipes axis), the blasts sand is delivered at a point at one side of said axis only, and consequently, either the pipe must be rotated relative to the nozzle, or the nozzle must be rotated relative to the pipe, in order to cover the entire interior area of the pipe. If the nozzle must be rotated relative to the pipe, this must be done in a reasonably accurately controlled fashion, otherwise areas within the pipe will be unevenly sandblasted, but when the jet is rotated mechanically or by hand, it must be supported for rotation in bearings which are necessarily located close to the nozzle, within the pipe, and which are inevitably subjected to the abrasive effect of the sandblast material and of the dust created by its use. Such bearings quickly deteriorate, and this manner of operation has been found to be unsatisfactory. Moreover, such procedure is extremely slow, and has been said, is likely to be uneven in its result.
The same objection above noted when the nozzle is rotated occurs where the nozzle itself may be stationary and the sand blast material discharged therefrom axially of the pipe is deflected to one side of such axis for impingement thereof against the inner side of the pipe. Such attempts have been made and the objectionable uneven result has not been corrected or changed where the deflector is rotated to progressively deflect the material against the sides of the pipe around its axis, and in this latter instance the abrasive effect 0n the relatively moving parts is also detrimental to the life and accuracy of the Sandblasting tool.
If, on the other hand, the pipe must be rotated relative to the jet, this requires handling of the pipe, which is often heavy, and special rigging must be used to support it during the Sandblasting operation and to traverse it so that it is s-andblasted the whole of its length. This is dicult, expensive and tedious, and moreover, precludes the possibility of Sandblasting the interior of stationarily supported pipe or the interior of a lot of pipe stacked in the pipe yard, or on racks. Because of these difficulties, this procedure has proven unsatisfactory.
An object of the present invention is to provide a tool for Sandblasting the interior of pipes, which overcomes the difficulties mentioned, and which enables the 'cleaning of the interior of pipes evenly, accurately, thoroughly, and yet quickly and cheaply.
Likewise it is an object of the invention to provide such a tool in which there are no parts which are relatively movable during the Sandblasting operation, and which therefore is free from bearing difficulties.
It is also an object of the invention to provide a tool of the nature and for the purpose indicated which will be subject to the minimum of wear, and which, at points of maximum wear, will be formed of materials capable of ready replacement, and of inherently long wearing qualities.
A further object of the invention is to provide a tool of the above nature which can be drawn or pushed by hand or by a simple feed mechanism through a pipe from end to end thereof, and which can be kept axially centered within the pipe, and which is adjustable to enable its positioning thus in pipes of varying size.
An added object of the invention is the provision of a tool that is adapted to be moved through the interior of a pipe to be cleaned axially of such pipe and which tOol includes a discharge nozzle and a deector that are stationary relative to each other during such movement of the tool through the pipe and which nozzle and deector are so arranged that Sandblasting material will be discharged within the pipe axially thereof, and on its axis from the nozzle and will be deflected to impinge the inner side of the pipe about a circle all at once without rotating the nozzle or the deector relative to each other or relative to the pipe.
The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawing, showing by way of example, a preferred embodiment of the inventive idea.
The drawing shows a pipe in axial section in the process of being sandblasted, the Sandblasting tool being shown in side elevation, but with parts broken away.
The pipe which is in the process of being cleaned is indicated in the drawing at P. This pipe is illustrated as having been cleaned at the left hand end, and only a portion at the right hand end still has an incrustation of scale, as indicated at S. The direction of movement of the Sandblasting tool is indicated by the arrow A.
The tool comprises a nozzle 1, to which sand is conveyed by air under pressure through a suitable hose 10 of indeterminate length, coupled to the nozzle at 11. The nozzle 1 is removably mounted in the coupling 11, and said nozzle is preferably of extremely hard, abrasion-resisting material, such as tungsten carbide, and it is wholly straight, and is disposed coaxially with the hose and the pipe and directed axially along pipe P, by means which will be described shortly. Its function is to confine the blast material, but not to change its direction.
Spaced a suitable distance beyond the end of the nozzle outwardly of its discharge opening, and in axial alignment with it is a deflector 2. This dellector is of generally conical shape, with its vertex 20 nearest to the exit of the nozzle 1, but spaced from the latter. The surface of the deilector 2 is preferably formed along a curve, as indicated at 21, so that tangents to this curve at successive points from the vertex toward the base 22, and lying in a radial plane, are successively steeper with relation to the axis of the conical dellector 2. Preferably, but not necessarily, the curve 21 is formed as the arc of a circle struck from a point such as C, located on a line which is at 45 to the axis of the cone, and outwardly of a projec# tion of the margin of the cones base at 22, and likewise outwardly of its vertex at 20.
The function of this deflector is to change the direction of the blast material. It is likewise of very hard mate-` rial, such as tungsten carbide, already mentioned, but since it'has surfaces angularly disposed relative tothe direction of the sandblast and impinged thereby, it will inevitably wear in time, even more than the nozzle, which" E has no such angularly disposed surfaces, and so it is removably mounted in a base mount 3, the two being indicated at 23 as relatively threadedly connected, whereby the deflector 2 may be removed when badly worn and a new one may be supplied to replace it.
It is preferred that the deflector and the nozzle be iixedly spaced in use, one from the other (although the spacing m-ight be variable) so that they may be moved conjointly axially of the pipe. To such ends spacers or struts 4 are employed, being preferably in the form of simple bars or straps of metal, these extending from the ring or collar 41 which surrounds and is mounted upon the coupling 11 at the base of the nozzle, to the base mount 3 which supports the deector 2. Although these spacer bars 4 are disposed edgewise to the blast material as it leaves the deflector 2, they will inevitably wear from the abrasive material, hence they are removably secured in place, as by the bolts 40, and in addition, when wear occurs in the vicinity of the base circle 22 of the deector the notches so abraded in the spacers 4 may be filled with hard weld material, and thus they will have a reasonably long life. In any event, they are of simple form and readily replaced.
In order to support the assembly within pipes of varying diameter and to dispose the nozzle and cone with reasonable accuracy axially of the pipe, guide elements such as the bolts 42 are employed, these being threadedly received in the ring or collar 4l and in the base mount 3 respectively. Even though there may be but slight room for adjustment if a pipe of larger diameter is to be cleaned, the shorter guide bolts 42 may be removed and longer ones used to replace them. Thus any given tool may be used Within pipes of different diameter.
In use, an assembled tool of this nature, connected to any suitable source of abrasive, particulate material and of air under blast pressure is introduced into an end of the pipe to be cleaned and the blast is commenced. The particulate material is blown directly through the nozzle 1, never needing to depart from its axial path, and abr'ading the nozzle to only a minimum degree, and issues as a concentrated stream as indicated at 9. The vertex 20 is positioned as to lie approximately axially within this blast stream 9, and so the curved surfaces 21 deflects and diverts the stream 9 substantially equally in all radial directions, and changes it into a generally iiat conical sheetv of particles as indicated at 91, spreading quite evenly in all directions atv once from the base of the deector. No rotative parts are needed. Because a tangent to the curve 21 at the base circle 22 would be slanted with relation to the cones axis by reason of the location of its center of curva-ture as already described, and because the conical blast sheet 91 leaves the deflector at suchy a tangent, this sheet of particulate material is not directed outwardly perpendicularly to the axis but rather is inclined with respect to the axis. This is important in that the material, after striking the v/all of tne pipe does not tend to` pile up back of the conical sheet 91, but rather is forced ahead ot' this sheet as is indicated at 92. Also, because of the axial ydirection of discharge of the blast from the nozzle, as distinguished from a lateral discharge, a powerful suction is created through the pipe in the same direction as the blast discharge, which likewise tends to sweep sand and loosened rust, ete., out of the distant (right hand) end of the pipe.
Now it will befclear that by thus discharging and de-r tlectingthe particulate mass, and by shifting the tool and the conical sheet of particles axially within the pipe as, for example, in the direction of the arrow A, the scale S is cleaned simultaneously from the interior wall of the pipe and all around the 360 extent of theserwalls. and is similarly cleaned and progressively forced ahead as the tool is; shifted axially. If the shifting is accomplished at a: substantially constant rate, as is preferred, and as canY beedone byv anexperienced operator, the cleansingV is qui-te uniform. It has been found that a single passat a speed which is generally related to the quantity of particles and the area of the pipe wall-that is to say, which is reasonably related to the number of particles striking within a given unit area in a given unit of timewill effect quite satisfactory cleansing. Moreover, the normal procedure is to pass the tool once through the pipe in one direction to remove most of the incrustation, and then to Withdraw it in the reverse direction, to polish the pipe and to remove any residue, so that, in effect, the pipe is sandblasted interiorly with two passes, and thus in a fraction of the time commonly required the pipe is thoroughly cleaned; the abraded and abrading material is pushed ahead out of the distant end of the pipe, and the entire operation can be accomplished without any handling ot any length of pipe. Indeed, it is possible to clean an entire stack of pipes or a fixed installation of tubes without disturbing the stack or the installation, provided, ot course, in the case of the tubes their opposite end are open.
While the operation is disclosed above as a Sandblasting operation, and that will constitute the usual practice, it will be clear that the particles m-ay be larger, and the operation will then become a shot-peening operation. The tool is well suited to such a modification, and it is intended to include such an operation within the term Sandblasting as used herein.
l. A tool for Sandblasting the interior of pipe and the like comprising: a straight, rigid, open ended tubular nozzle adapted to be positioned within the pipe to be cleaned coaxially therewith, means for connecting one end of said nozzle with a source of Sandblasting material and with air under pressure for discharge of said material and air from the opposite end of said nozzle, a generally conical deector coaxial with said nozzle spaced axially outwardly of said opposite end and having its vertex directed toward said opposite end, means for securing said nozzle and said deector together' against rotation of one relative to the other during movement of said nozzle and said deector through su'ch pipe, said means `for securing said nozzle and said deflector together comprising a plurality of strips spaced from' each other and around and radially outwardly of the 'axis of said nozzle and said deflector with their flat sides disposed substantially radially of said axis, means for connecting one of the ends of said bars rigid with said nozzle and rneans for connecting the other ends of said bars rigid with said reector.
2. A tool for Sandblasting the interior of pipe and the like comprising: a rigid, open ended, tubular nozzle adapted to be positioned within the pipe to be cleaned and interiorly free from obstruction to the movement of Sandblasting material therethrough from one end to the other end thereof a'nd for discharge from said other end, a generally conical deector providing a coaxial vertex and circular base, said deflector being coaxial with said nozzle and spaced from said other end of said nozzle with its vertex directed toward said nozzle, a plurality of bars extending longitudinally of said axis equally spaced from the latter outside the axially projected confines of said nozzle and said` deector, means for securing one of the ends of said'y bars rigid with said nozzle and means for securing the other ends of said bars rigid with said deector.
3. A tool for Sandblasting the interior of pipe and the like comprising: a rigid,r open ended, tubular nozzle adapted to be positioned Within the pipe to be cleaned and interiorly free fromobstruction to the movement of Sandblasting material therethrough from one end to the other end thereof and for discharge from said other end, a generally conical deector providing a coaxial vertex and circular base, said deector being coaxial with said nozzle and spaced from said other end of said nozzle withitsvertex directed toward said nozzle, a plurality of bars extending longitudinally ofv said axis equally spaced from the latter outside the axially projected contines of said nozzle yand said detlector, means for securing one of the ends of said bars rigid with said nozzle and means for securing the other ends of said bars rigid with said deilector, the sides of said deilector between said vertex and said circular base being curved about centers in a circle disposed in a plane perpendicular to said axis and coaxial with the latter and positioned between said deiiector and said nozzle and which centers are spaced radially outwardly of said axially projected connes and the said axially projected confines of the discharge end of said nozzle being less than the diameter of the circular base of said deflector whereby Sandblasting material discharged vfrom said other end of said nozzle and striking said deector will be angularly deflected -from the sides of said deflector generally radially outwardly and generally in the direction of movement of said material from said nozzle to said deector.
4. A tool for Sandblasting the interior of pipe and the like comprising: a rigid, open ended, tubular nozzle adapted to be positioned within the pipe to be cleaned and interiorly free from obstruction to the movement of Sandblasting material therethrough from one end to the other end thereof and for discharge from said other end, a generally conical deilector providing a coaxial vertex and circular base, said deector being coaxial with said nozzle and spaced from said other end of said nozzle with its vertex directed toward said nozzle, a plurality of bars extending longitudinally of said axis equally spaced from the latter outside the axially projected confines of said nozzle and said deliector, means for securing one of the ends of said bars rigid with said nozzle, and means for securing the other ends of said bars rigid with said dellector, the sides of said deector between sai-d vertex and said circular base being curved about centers in a circle disposed in a plane perpendicular to said axis and coaxial with the latter and positioned between said deector and said nozzle and which centers are spaced radially outwardly of said axially projected contines and the said axially projected contines of the discharge end of said nozzle being less than the diameter of the circular base of said dellector whereby Sandblasting material discharged from said other end of said nozzle and striking said deiiec tor will be angularly deflected from the sides of said deflector generally radially outwardly and generally in the direction of movement of said material yfrom said nozzle to said deector, said nozzle being of substantially uniform inside diameter for discharge of said Sandblasting material from said other end in a concentrated stream of substantially uniform diameter.
5. A tool for Sandblasting the interior of pipe and the like comprising: a rigid, open ended, tubular nozzle adapted to be positioned within the pipe to be cleaned and interiorly free from obstruction to the movement of Sandblasting material therethrough from one end to the other end thereof and for discharge Vfrom said other end, a generally conical deflector providing a coaxial vertex and circular base, said deliector being coaxial with said nozzle and spaced lfrom said other end of said nozzle with its vertex directed toward said nozzle, a plurality of bars extending longitudinally of said axis equally spaced from the latter outside the axially projected contines of said nozzle and said deflector, means 'for securing one of the ends of said bars rigid with said nozzle and means for securing the other ends of said bars rigid with said deecton means connected with said nozzle and said deilector for supporting them spaced coaxially within a pipe for conjoint movement of said nozzle and deflector through such pipe axially of the latter.
References Cited in the tile of this patent UNITED STATES PATENTS